i dont think you can..did you do the qualifiers before you started your career??
lol i hate the trucks they are probably the hardest to drive,
but restart the whole game and keep doing the qualifiers if your just looking to skip the trucks,it took me literally 7 restarts to do good enough in the qualifiers to even get into the top series

yeah, it just takes forever! I like dealing with the pit strategy. What I really want to do eventually is buy one of those racing brackets that comes with a seat and a mount for your pedals and wheel. Then it would feel like more of a race (and I'd like the wheel more). I bought a wheel before, but I hated it because I couldn't mount it anywhere and ended up using it under my legs (which are too big). I played forza 2 like that for maybe a week and said to hell with it.